ARCLIGHT
Free action game · plays in your browser · made with Opus 5.5
Play ARCLIGHT free in your browser: an action game with nothing to download and no sign-up. If you came looking for Magic, this is built in that mould. It was written by Opus 5.5, and the prompt behind it is printed further down this page.
About ARCLIGHT
ARCLIGHT is a pixel-art survivor game with a persistent skill tree. You play a lightning mage in an arena that fills with monsters. Your spells cast themselves; your job is to move, collect the crystals the dead leave behind, and pick an upgrade card every time you level up. Survive seven minutes and the biome's boss arrives, and killing it opens the next biome. If you fall, the essence you gathered is kept and spent in the Grimoire, a skill tree that unlocks new spells and permanent power, so every run makes the next one stronger.
The ground is the weapon. Lightning that hits water electrocutes the whole pool and everything standing in it. Fire on oil turns into a blaze, on grass and trees it spreads as wildfire, and on water it makes scalding steam. Frost freezes water and the enemies standing in it, and the next hit shatters them. Five biomes, a marsh, tar fields, a frozen lake, a burning wood and a storm-lashed peak, each lean on a different element and send enemies that resist one of yours, with bosses that charge, slam and call down strikes you have to dodge. Move with WASD or the arrow keys, press Space for a Storm Surge that charges from kills, and pick cards with 1, 2 or 3. Start by leading the horde through the marsh water before your chain lightning fires.
How was ARCLIGHT made?
The prompt behind ARCLIGHT
After a first game, Claude had pitched a few options; the user picked this one, pasting the pitch: "Lightning-mage survivor game. Spells chain and react with the environment: fire and oil, lightning and water. A skill tree carries over between biomes. It has the most action." and asked: "can you create, like, a new folder and create this one as well? But, again, with the same principle, with improvement that stays, and, yeah, just this arc." The build: a 72x72-tile arena whose ground reacts (fire spreading over oil, grass and trees; lightning flooding connected water; frost freezing it; rain making puddles; every change reverting after a while), seven auto-cast spells, seven passives, level-up cards, five enemy types, elites, a mid-boss and a boss per biome with telegraphed charges, slams, bullet rings and lightning strikes, a Storm Surge on Space, and a 20-node Grimoire skill tree bought with essence that is kept on death. Everything runs in a DOM-free simulation, so a Node bot that kites the horde could play the whole five-biome career on the real code; it found that spells needed to scale with each biome, that a dense forest turned one biome into a wall, and that ranged spitters rather than bombers were what killed runs. All pixel art and sound are generated in code.
Categories and tags
Questions about ARCLIGHT
6
- Is ARCLIGHT free to play?
- Yes. ARCLIGHT is free, runs in your browser, and needs no account. Nothing to download, no plugin, no sign-up — open the page and play.
- Do I need to download or install ARCLIGHT?
- No. ARCLIGHT runs entirely in the browser on desktop. There is nothing to install and no launcher to sign in to.
- Which AI model made ARCLIGHT?
- ARCLIGHT was written by Opus 5.5, a model from Anthropic, using Claude Code. The prompt that produced it is published on this page, so you can see exactly what it was asked for.
- What is ARCLIGHT like?
- It is an action game, filed by its creator under Magic and Horde and Skill Tree. ARCLIGHT is a pixel-art survivor game with a persistent skill tree.
- Does ARCLIGHT keep a high score?
- Yes. Any score ARCLIGHT reports goes to the leaderboard under the game, and you do not need an account for it to count.
- How much did ARCLIGHT cost to make?
- $10.30 in model usage, running Opus 5.5, over about 53 minutes of building. Every game here records what it cost, which is the point of the site.
Version 1.0